Magnetic Resonance Myocardial Feature Tracking Research Articles

Time Course of Left Ventricular Strain Assessment via Cardiovascular Magnetic Resonance Myocardial Feature Tracking in Takotsubo Syndrome.

Background: Although takotsubo syndrome (TTS) is characterized by transient systolic dysfunction of the left ventricle (LV), the time course and mechanism of LV function recovery remain elusive. The aim of this study is to evaluate cardiac functional recovery in TTS via serial cardiac magnetic resonance feature tracking (CMR-FT). Methods: In this Japanese multicenter registry, patients with newly diagnosed TTS were prospectively enrolled. In patients who underwent serial cardiovascular magnetic resonance (CMR) imaging at 1 month and 1 year after the onset, CMR-FT was performed to determine the global circumferential strain (GCS), global radial strain (GRS) and global longitudinal strain (GLS). We compared LV ejection fraction, GCS, GRS and GLS at 1 month and 1 year after the onset of TTS. Results: Eighteen patients underwent CMR imaging in one month and one year after the onset in the present study. LV ejection fraction had already normalized at 1 month after the onset, with no significant difference between 1 month and 1 year (55.8 ± 9.2% vs. 58.9 ± 7.3%, p = 0.09). CMR-FT demonstrated significant improvement in GCS from 1 month to 1 year (-16.7 ± 3.4% vs. -18.5 ± 3.2%, p < 0.01), while there was no significant difference in GRS and GLS between 1 month and year (GRS: 59.6 ± 24.2% vs. 59.4 ± 17.3%, p = 0.95, GLS: -12.8 ± 5.9% vs. -13.8 ± 4.9%, p = 0.42). Conclusions: Serial CMR-FT analysis revealed delayed improvement of GCS compared to GRS and GLS despite of rapid recovery of LV ejection fraction. CMR-FT can detect subtle impairment of LV systolic function during the recovery process in patients with TTS.

Cardiovascular magnetic resonance myocardial feature tracking for the determination of left atrial strain in hypertensive left ventricular hypertrophy and hypertrophic cardiomyopathy

To measure the left atrial (LA) function in patients with hypertrophic cardiomyopathy (HCM; with [OHCM] and without obstruction [NOHCM]) and hypertension-related left ventricular hypertrophy (H-LVH) using cardiovascular magnetic resonance imaging feature tracking (CMR-FT). Patients who met the criteria for HCM (n=68), H-LVH (n=46), and 30 healthy controls participated. Left atrial strain was analysed using CMR-FT in cine images with two and four chambers. The strain rate and LA strain measurements showed that patients with HCM, and H-LVH had impaired conduit and reservoir functions (versus controls). These capacities were more severely impaired in OHCM than those seen in NOHCM and H-LVH. The LA volume parameters (LAVIpac, LAVImin and LAVImax) from the OHCM group were higher than both the NOHCM and H-LVH groups (all p<0.05). There were differences between the OHCM and H-LVH groups in terms of the parameters for LA reservoir function (εs), booster pump function (SRa), and conduit function (SRe, LA passive EF, εe; p<0.05). The strongest correlations included the associations between LA total EF and εs, εe and LA passive EF, and SRe and LA passive EF. CMR-FT can reliably identify LA dysfunction and deformation in the early stages of HCM and H-LVH.

Risk stratification of patients with Brugada syndrome: the impact of myocardial strain analysis using cardiac magnetic resonance feature tracking

ObjectiveThis study evaluated the prognostic significance of cardiac magnetic resonance myocardial feature tracking (CMR-FT) in patients with Brugada syndrome (BrS) to detect subclinical alterations and predict major adverse events (MAE). MethodsCMR was performed in 106 patients with BrS and 25 healthy controls. Biventricular global strain analysis was assessed using CMR-FT. Patients were followed over a median of 11.6 [8.8 ± 13.8] years. ResultsThe study cohort was subdivided according to the presence of a spontaneous type 1 ECG (sECG) into sBrS (BrS with sECG, n = 34 (32.1%)) and diBrS (BrS with drug-induced type 1 ECG, n = 72 (67.9%)). CMR-FT revealed morphological differences between sBrS and diBrS patients with regard to right ventricular (RV) strain (circumferential (%) (sBrS −7.9 ± 2.9 vs diBrS - 9.5 ± 3.1, p = 0.02) and radial (%) (sBrS 12.0 ± 4.3 vs diBrS 15.4 ± 5.4, p = 0.004)). During follow-up, MAE occurred in 11 patients (10.4%). Multivariable analysis was performed to identify independent predictors for the occurrence of events during follow-up. The strongest predictive value was found for RV circumferential strain (OR 3.2 (95% CI 1.4 - 6.9), p = 0.02) and RVOT/BSA (OR 3.1 (95% CI 1.0 - 7.0), p = 0.03). ConclusionsMyocardial strain analysis detected early subclinical alterations, prior to apparent changes in myocardial function, in patients with BrS. While usual functional parameters were within the normal range, CMR-FT revealed pathological results in patients with an sECG.Moreover, RV circumferential strain and RVOT size provided additional prognostic information on the occurrence of MAE during follow-up, which reflects electrical vulnerability.

Comprehensive assessment of left atrial and ventricular remodeling in paroxysmal atrial fibrillation by the cardiovascular magnetic resonance myocardial extracellular volume fraction and feature tracking strain

Atrial fibrillation (AF) is a progressive disease that starts with structural or functional changes in the left atrium and left ventricle, and evolves from paroxysmal toward sustained forms. Early detection of structural or functional changes in the left atrium and left ventricle in the paroxysmal stage could be useful for identifying a higher risk of progression to persistent AF and future cardio-cerebrovascular events. The aim of this study was to test the hypothesis that the feature tracking (FT) left atrial (LA) strain and left ventricular (LV) extracellular volume fraction (ECV) derived from cardiovascular magnetic resonance (CMR) could detect early changes in remodeling of the left atrium and ventricle in the paroxysmal AF (PAF) stage. The participants were comprised of 106 PAF patients (age, 66.1 ± 10.7 years; 66% male) who underwent clinical CMR before pulmonary vein isolation and 20 control subjects (age, 68.3 ± 8.6 years; 55% male). The CMR-FT LA strain/phasic function and LV-ECV were compared between the PAF and control groups. The total and passive LA empty fraction (LAEF) and LA strain (corresponding to LA reservoir and conduit function) were decreased in the PAF group as compared to the control group. However, active LAEF (corresponding to the LA booster pump function) did not differ significantly between the PAF group (33.9 ± 10.9%) and control group (37.9 ± 13.3%, p = 0.15), while the active LA strain (corresponding to the LA booster pump function) was significantly decreased in the PAF group (11.4 ± 4.3 vs. 15.2 ± 5.6%, p = 0.002). The LV-ECV was significantly greater in the PAF group (28.7 ± 2.8%) than control group (26.6 ± 2.0%, p = 0.002). In the PAF group, the LV-ECV correlated significantly with the E/e′ and LA volume index. Regarding the LA strain, correlations were seen between the LV-ECV and both the reservoir function and conduit function. CMR-FT LA strain in combination with the LV-ECV in a single clinical study offers a potential imaging marker that identifies LA/LV remodeling including subtle LA booster pump dysfunction undetectable by the conventional booster pump LAEF in the PAF stage.

CMR feature tracking remote myocardial strain analyses for optimized risk prediction following acute myocardial infarction

Abstract Funding Acknowledgements Type of funding sources: None. Background Cardiac magnetic resonance myocardial feature tracking (CMR-FT) derived global strain assessments provide incremental prognostic information in patients following acute myocardial infarction (AMI). Functional analyses of the remote myocardium (RM) are scarce and whether they provide an additional prognostic value in these patients is unknown. Methods 1052 patients following acute myocardial infarction were included. CMR imaging and strain analyses as well as scar size quantification were performed after reperfusion by primary percutaneous coronary intervention. The occurrence of major adverse cardiac events (MACE) within 12 months after the index event was defined as primary clinical endpoint. Results Patients with MACE had significantly lower RM circumferential strain (CS) compared to those without MACE. A cut-off value for RM CS of -25.8% best identified high-risk patients (p &amp;lt; 0.001 on log-rank testing) and impaired RM CS was a strong predictor of MACE (HR 1.05, 95% CI 1.07-1.14, p = 0.003). RM CS provided further risk stratification amongst patients considered at risk according to established CMR parameters for 1.) patients with reduced left ventricular ejection fraction (LVEF) ≤ 35 % (p = 0.002 on log-rank testing), 2.) patients with reduced global circumferential strain (GCS) &amp;gt; -18,3 % (p = 0.015 on log-rank testing), and 3.) patients with large microvascular obstruction ≥ 1.46 % (p = 0.038 on log-rank testing). Conclusion CMR-FT derived RM CS is a useful parameter to characterize the response of RM and allows improved stratification following AMI beyond commonly used parameters, especially of high-risk patients.

Quantification of Biventricular Myocardial Strain Using CMR Feature Tracking: Reproducibility in Small Animals.

Myocardial strain is a well-validated parameter for evaluating myocardial contraction. Cardiovascular magnetic resonance myocardial feature tracking (CMR-FT) is a novel method for the quantitative measurements of myocardial strain from routine cine acquisitions. In this study, we investigated the influence of temporal resolution on tracking accuracy of CMR-FT and the intraobserver, interobserver, and interstudy reproducibilities for biventricular strain analysis in mice from self-gated CMR at 11.7 T. 12 constitutive nexilin knockout (Nexn-KO) mice, heterozygous (Het, N = 6) and wild-type (WT, N = 6), were measured with a well-established self-gating sequence twice within two weeks. CMR-FT measures of biventricular global and segmental strain parameters were derived. Interstudy, intraobserver, and interobserver reproducibilities were investigated. For the assessment of the impact of the temporal resolution for the outcome in CMR-FT, highly oversampled semi-4 chamber and midventricular short-axis data were acquired and reconstructed with 10 to 80 phases per cardiac cycle. A generally reduced biventricular myocardial strain was observed in Nexn-KO Het mice. Excellent intraobserver and interobserver reproducibility was achieved in all global strains (ICC range from 0.76 to 0.99), where global right ventricle circumferential strain (RCSSAX) showed an only good interobserver reproducibility (ICC 0.65, 0.11-0.89). For interstudy reproducibility, left ventricle longitudinal strain (LLSLAX) was the most reproducible measure of strain (ICC 0.90, 0.71-0.97). The left ventricle radial strain (LRSSAX) (ICC 0.50, 0.10-0.83) showed fair reproducibility and RCSSAX (ICC 0.36, 0.14-0.74) showed only poor reproducibility. In general, compared with global strains, the segmental strains showed relatively lower reproducibility. A minimal temporal resolution of 20 phases per cardiac cycle appeared sufficient for CMR-FT strain analysis. The analysis of myocardial strain from high-resolution self-gated cine images by CMR-FT provides a highly reproducible method for assessing myocardial contraction in small rodent animals. Especially, global LV longitudinal and circumferential strain revealed excellent reproducibility of intra- and interobserver and interstudy measurements.

Risk stratification of patients with Brugada syndrome (BrS): the impact of myocardial strain analysis using cardiac magnetic resonance myocardial feature tracking (CMR-FT)

Abstract Objectives This study evaluated the prognostic significance of cardiac magnetic resonance myocardial feature racking (CMR-FT) in patients with Brugada syndrome (BrS) to detect subclinical alterations and predict major adverse events (MAE). Methods and results CMR was performed in 106 patients (pts) with BrS. Biventricular global strain analysis was assessed using CMR-FT. Pts were followed for a mean of 11.1±3.5 years. The study cohort was subdivided according to the presence of a spontaneous type 1 ECG (sECG), into sBrS (BrS with sECG, n=34 (32.1%)) and diBrS (BrS with drug-induced type 1 ECG, n=72 (67.9%)). Both left and right ventricular (RV) ejection fraction were reduced within the normal range in sBrS pts. CMR-FT revealed morphological differences between sBrS and diBrS pts regarding RV strain (circumferential (%) (sBrS 7.9±2.9 vs diBrS −9.5±3.1, p=0.02) and radial strain (%) (sBrS 12.0±4.3 vs diBrS 15.4±5.4, p&amp;lt;0.01)). During follow up, MAE were noted in 12 pts (11.3%). The presence of a sECG was the strongest predictor for MAE (OR 0.70, 95% CI 0.53–0.90; p=0.008). RV global circumferential strain (GCS) was also associated with MAE (OR 0.16, 95% CI 0.03–0.82; p=0.03). A risk model which combined these two identified predictors showed a substantial risk increase for patients with both sECG and reduced RV-GCS. Conclusion Myocardial strain analysis detected early subclinical alterations, prior to apparent changes in myocardial function, in patients with BrS. Moreover, RV-GCS provided additional prognostic information on the occurrence of MAE during follow-up. Funding Acknowledgement Type of funding source: Foundation. Main funding source(s): Deutsches Zentrum für Herz- und Kreislaufforschung (DZHK), German Centre for Cardiovascular Research

Functional and prognostic implications of cardiac magnetic resonance feature tracking-derived remote myocardial strain analyses in patients following acute myocardial infarction

BackgroundCardiac magnetic resonance myocardial feature tracking (CMR-FT)-derived global strain assessments provide incremental prognostic information in patients following acute myocardial infarction (AMI). Functional analyses of the remote myocardium (RM) are scarce and whether they provide an additional prognostic value in these patients is unknown.Methods1034 patients following acute myocardial infarction were included. CMR imaging and strain analyses as well as infarct size quantification were performed after reperfusion by primary percutaneous coronary intervention. The occurrence of major adverse cardiac events (MACE) within 12 months after the index event was defined as primary clinical endpoint.ResultsPatients with MACE had significantly lower RM circumferential strain (CS) compared to those without MACE. A cutoff value for RM CS of − 25.8% best identified high-risk patients (p < 0.001 on log-rank testing) and impaired RM CS was a strong predictor of MACE (HR 1.05, 95% CI 1.07–1.14, p = 0.003). RM CS provided further risk stratification among patients considered at risk according to established CMR parameters for (1) patients with reduced left ventricular ejection fraction (LVEF) ≤ 35% (p = 0.038 on log-rank testing), (2) patients with reduced global circumferential strain (GCS) > − 18.3% (p = 0.015 on log-rank testing), and (3) patients with large microvascular obstruction ≥ 1.46% (p = 0.002 on log-rank testing).ConclusionCMR-FT-derived RM CS is a useful parameter to characterize the response of the remote myocardium and allows improved stratification following AMI beyond commonly used parameters, especially of high-risk patients.Trial registrationClinicalTrials.gov, NCT00712101 and NCT01612312Graphic abstractDefining remote segments (R) in the presence of infarct areas (I) for the analysis of remote circumferential strain (CS). Remote CS was significantly lower in patients who suffered major adverse cardiac events (MACE) and a cutoff value for remote CS of − 25.8% best identified high-risk patients. In addition, impaired remote CS ≥ − 25.8 % (Remote −) and preserved remote CS < − 25.8 % (Remote +) enabled further risk stratification when added to established parameters like left ventricular ejection fraction (LVEF), global circumferential strain (GCS) or microvascular obstruction (MVO).

Cardiac Magnetic Resonance Myocardial Feature Tracking for Optimized Risk Assessment After Acute Myocardial Infarction in Patients With Type 2 Diabetes.

Type 2 diabetes predicts outcome following acute myocardial infarction (AMI). Since underlying mechanics are incompletely understood, we investigated left ventricular (LV) and left atrial (LA) pathophysiological changes and their prognostic implications using cardiovascular magnetic resonance (CMR). Consecutive patients (N = 1,147; n = 265 with diabetes, n = 882 without diabetes) underwent CMR 3 days after AMI. Analyses included LV ejection fraction (LVEF); global longitudinal strain (GLS) and circumferential and radial strains; LA reservoir, conduit, and booster pump strains; and infarct size, edema, and microvascular obstruction. Predefined end points were major adverse cardiovascular events (MACE) within 12 months. Patients with diabetes had impaired LA reservoir (19.8% vs. 21.2%, P < 0.01) and conduit (7.6% vs. 9.0%, P < 0.01) strains but not ventricular function or myocardial damage. They were at higher risk of MACE than patients without diabetes (10.2% vs. 5.8%, P < 0.01), with most MACE occurring in patients with LVEF ≥35%. While LVEF (P = 0.045) and atrial reservoir strain (P = 0.024) were independent predictors of MACE in patients without diabetes, GLS was in patients with diabetes (P = 0.010). Considering patients with diabetes and LVEF ≥35% (n = 237), GLS and LA reservoir strain below median were significantly associated with MACE. In conclusion, in patients with diabetes, LA and LV longitudinal strain permit optimized risk assessment early after reperfused AMI with incremental prognostic value over and above that of LVEF.

Right Atrial Deformation Using Cardiovascular Magnetic Resonance Myocardial Feature Tracking Compared with Two-Dimensional Speckle Tracking Echocardiography in Healthy Volunteers

Speckle tracking echocardiography (STE), and more recently, cardiovascular magnetic resonance myocardial feature tracking (CMR-FT) provides insight into all phases of atrial function. The aim of our study was to compare all phases of RA strain using CMR-FT and STE and also assess the relationship between RA and LA strain. A total of 61 healthy volunteers with mean age of 45 ± 13 years had adequate tracking for analysis on CMR-FT and 2D-STE. Females had larger RA reservoir strain (39 ± 15% vs. 32 ± 13%, p = 0.046) and conduit strain (26 ± 12% vs. 20 ± 9%, p = 0.03) when compared to males, but was not the case with booster strain (14 ± 7% vs. 12 ± 6%, p = 0.45). In comparison with STE derived strain, the RA reservoir and conduit strain were not significantly different between CMR-FT and the three echocardiography gating methods (p > 0.05 for all). Noticeably, there were no significant differences in strain and strain rate between RA and LA function using CMR-FT (p > 0.05 for all). RA strain and strain rate using CMR-FT had fair and good intra- and inter-observer reproducibility and had superior reproducibility compared to STE derived strain.

FUNCTIONAL AND PROGNOSTIC IMPLICATIONS OF CARDIAC MAGNETIC RESONANCE FEATURE TRACKING DERIVED REMOTE MYOCARDIAL STRAIN ANALYSES IN PATIENTS FOLLOWING ACUTE MYOCARDIAL INFARCTION

Cardiac magnetic resonance myocardial feature tracking (CMR-FT) derived global strain assessments provide incremental prognostic information in patients following acute myocardial infarction (AMI). Functional analyses of the remote myocardium (RM) are scarce and whether they provide an additional

565 Impact of right atrial physiology on heart failure and adverse events after myocardial infarction

Abstract Background Right ventricular (RV) function is a known predictor of adverse events in heart failure and following acute myocardial infarction (AMI). While right atrial (RA) involvement is well characterized in pulmonary arterial hypertension, its relative contributions to adverse events following AMI especially in patients with heart failure and congestion needs further evaluation. Methods 1235 MI patients underwent CMR after primary percutaneous coronary intervention (PCI) in 15 centers across Germany (n = 795 with ST-elevation MI and 440 with non ST-elevation MI). Right atrial (RA) performance was evaluated using cardiac magnetic resonance myocardial feature tracking (CMR-FT) for the assessment of RA reservoir (total strain εs), conduit (passive strain εe), booster pump function (active strain εa) and associated strain rates (SR) in a blinded core-laboratory. The primary clinical endpoint was the occurrence of major adverse cardiac events (MACE) 12 months post MI. Results RA reservoir (εs p = 0.061, SRs p = 0.049) and conduit functions (εe p = 0.006, SRe p = 0.030) were impaired in patients with MACE as opposed to RA booster pump (εa p = 0.579, SRa p = 0.118) and RA volume index (p = 0.866). RA conduit function was associated with clinical onset of heart failure and MACE independently of RV systolic function (multi-variable analysis HR 0.95, 95% CI 0.91-0.99, p = 0.006) while RV systolic function was no independent prognosticator (HR 0.98, 95% CI 0.96-1.00, p = 0.055). Furthermore, RA conduit strain identified low- and high-risk groups within patients with relatively preserved and reduced RV and LV systolic functions (p &amp;lt; 0.019 on log rank testing). Conclusions Right atrial impairment is a distinct feature and independent risk factor in patients following AMI and can be easily assessed using CMR-FT derived quantification of RA strain.

564 Cardiac magnetic resonance myocardial feature tracking for optimized risk assessment after acute myocardial infarction in patients with type 2 diabetes

Abstract Objective Type 2 diabetes mellitus (T2DM) associates with worse cardiovascular outcome following acute myocardial infarction (AMI) as compared to non-diabetic patients. Since the mechanisms behind these observations are not fully understood we aimed to quantify the underlying pathophysiology on ventricular and atrial levels and study their prognostic implications using cardiovascular magnetic resonance (CMR) quantitative feature-tracking (FT) and tissue characterization. Research Design and Methods: A total of 1147 consecutive patients with AMI (n = 265 with diabetes; n = 882 without diabetes) undergoing cardiac magnetic resonance (CMR) imaging in median 3 days after AMI were included in this multicenter study. Left ventricular (LV) function and volumetry included LV ejection fraction (LV-EF), global longitudinal (GLS), radial (GRS) and circumferential strain (GCS) as well as left atrial (LA) strain and strain rate parameters of LA reservoir, conduit and booster pump function. LV damage assessment included infarct size (IS), edema and microvascular obstruction (MO). The clinical study endpoint was the rate of major adverse cardiovascular events (MACE) at 12 months. Results T2DM patients had impaired LA reservoir (19.8 vs. 21.2%, p &amp;lt; 0.01) and conduit strains 7.6 vs. 9.0%, p &amp;lt; 0.01) but no differences in ventricular function or myocardial damage. They were at higher risk of MACE than non-diabetic patients (10.2% vs. 5.8%, p &amp;lt; 0.01) with the majority of MACE occurring in patients with LVEF ≥ 35%. Whilst LVEF was an independent predictor of adverse events in non-diabetic patients (p = 0.04 on multivariable analysis), LV GLS as well as LA strain emerged as independent predictors of poor prognosis in patients with diabetes (p &amp;lt; 0.02 on multivariable analysis). Considering patients with diabetes and LVEF ≥35% (n = 237), GLS and LA reservoir strain below median were significantly associated with higher 12-month event rates. Conclusions In patients with diabetes, LA and LV longitudinal strain permit optimized risk assessment early after reperfused AMI with incremental prognostic value over and above LVEF.

131Left atrial phasic function in heart failure with preserved ejection fraction: cardiac magnetic resonance myocardial feature tracking, invasive hemodynamics and outcome

Abstract Background Global left atrial (LA) size and function have been shown to be associated with adverse events in heart failure with preserved ejection fraction (HFpEF). The machanism of coupling from left heart failure to pulmonary circulation is still controversially discussed. Purpose To study the prognostic most relevant determinant of LA size and function and its backward and forward interplay. Methods 188 HFpEF patients were prospectively enrolled and underwent baseline clinical assessment, cardiac magnetic resonance imaging (CMR) and invasive hemodynamic assessment. Coronary artery disease was ruled out by coronary angiography. 92 patients were in atrial fibrillation (AF), 96 in sinus rhythm. LA size and function were assessed by CMR including LA strain imaging by myocardial feature tracking (Figure 1A &amp; B). Results Patients in AF had more pronounced dilatation of all phasic LA volumes and reduction of all phasic LA functions when compared to sinus rhythm (each p&lt;0.001 respectively). After 31 (9–57) months 66 patients reached the combined endpoint defined as combination from hospitalization due to heart failure and cardiovascular death. In AF no atrial functional or volume parameter was correlated to outcome. In contrast in sinus rhythm several phasic LA volume and functional parameters were associated with outcome. After multivariate cox regression analysis only reduced total LA ejection fraction and conduit strain rate were still predictive for worse outcome (p=0.031 and &lt;0.001 respectively). After adjustment for known risk factors in HFpEF like age, six minute walking distance (6MWD), systolic pulmonary artery pressure (sPAP) and right ventricular ejection fraction as derived by CMR only impaired LA conduit strain rate remained predicitve for cardiovascular events (p=0.001). In contrast to LA booster pump function LA conduit function parameters were significantly correlated to reduced 6MWD (Figure 1C) and coupled backwards to pulmonary vasculature via correlation to sPAP and pulmonary vascular resistance (PVR) but without coupling to CMR derived elevated LV extracellular volume and left ventricular end diastolic pressure. Conclusion Total LA ejection fraction plays a key role in the prognosis of HFpEF. This effect seems to be mainly related to its LA conduit function but not to LA booster pump function. LA conduit function correlates to impaired 6MWD, sPAP and PVR.

Cardiac magnetic resonance feature tracking for quantifying right ventricular deformation in type 2 diabetes mellitus patients

To determine the feasibility of deformation analysis in the right ventricle (RV) using cardiovascular magnetic resonance myocardial feature tracking (CMR-FT) in type 2 diabetes mellitus (T2DM) patients. We enrolled 104 T2DM patients, including 14 with impaired right ventricular ejection fraction (RVEF) and 90 with preserved RVEF, and 26 healthy controls in this prospective study. CMR was used to determine RV feature-tracking parameters. RV strain parameters were compared among the controls, patients with preserved and reduced RVEF. Binary logistic regression was used to predict RV dysfunction. Receiver operating characteristic analysis was used to assess the diagnostic accuracy. The agreement was tested by Bland–Altman analysis. Compared with controls, longitudinal and circumferential global peak strain (PS) and PS at mid-ventricular, apical slices were significantly decreased in T2DM patients with or without reduced RVEF (p < 0.05). Within the T2DM patients, the global longitudinal PS (GLPS) and the longitudinal PS at mid-ventricular segments were significantly reduced in the reduced RVEF group than in preserved RVEF groups (p < 0.05). GLPS was an independent predictor of RV dysfunction (odds ratio: 1.246, 95% CI: 1.037–1.496; p = 0.019). The GLPS demonstrated greater diagnostic accuracy (area under curve: 0.716) to predict RV dysfunction. On Bland-Altman analysis, global circumferential PS and GLPS had the best intra- and inter-observer agreement, respectively. In T2DM patients, CMR-FT could quantify RV deformation and identify subclinical RV dysfunction in those with normal RVEF. Further, RV strain parameters are potential predictors for RV dysfunction in T2DM patients.

Prognostic value of left atrial function by cardiovascular magnetic resonance feature tracking in hypertrophic cardiomyopathy.

Left atrium (LA) size has an important role in determining prognosis and risk stratification in hypertrophic cardiomyopathy (HCM). Cardiovascular magnetic resonance myocardial feature tracking (CMR-FT) is a novel technique for the quantification of LA function. Our aim was first to evaluate LA function by CMR-FT and volumetric analysis in patients with HCM; and secondly we sought to determine the association of LA-longitudinal strain (LA-LS) with major cardiovascular outcomes, particularly all cause mortality and heart failure. 75 patients with HCM and 75 control subjects underwent a conventional CMR study including assessment of LA function by CMR-FT (LA-LS) and volumetric analysis. A primary endpoint of all-cause mortality and secondary combined endpoint of hospital admission related to heart failure, lethal ventricular arrhythmias or cardiovascular death were defined. Compared to controls, LA-LS and all volumetric indices of LA function were significantly impaired in HCM even in patients with normal LA volume and normal LV filling pressures. LA-LS showed moderate-high correlation with LA-emptying fraction (total, active and passive LA-EF, r = 0.68, r = 0.67, r = 0.31, p < 0.001 for all) and with parameters of diastolic function (E/é, r = 0.4, p < 0.001). The age, minimum LA volume and % of LGE were independent predictors of LA-LS (p < 0.01 for all). During a mean follow-up of 3.3 ± 1.2years LA-LS was associated with the primary (HR: 0.85 (0.73-0.98), p = 0.02) and the secondary end-point (HR: 0.88 (0.82-0.96), p = 0.003). LA-LS by CMR-FT provides accurate measurements of LA function in HCM patients. LA-LS may become a novel potential predictor of poor cardiac outcomes, particularly cardiovascular mortality and HF.

Clinical applications of feature-tracking cardiac magnetic resonance imaging.

Cardiovascular diseases represent the leading cause of mortality and morbidity in the western world. Assessment of cardiac function is pivotal for early diagnosis of primitive myocardial disorders, identification of cardiac involvement in systemic diseases, detection of drug-related cardiac toxicity as well as risk stratification and monitor of treatment effects in patients with heart failure of various etiology. Determination of ejection fraction with different imaging modalities currently represents the gold standard for evaluation of cardiac function. However, in the last few years, cardiovascular magnetic resonance feature tracking techniques has emerged as a more accurate tool for quantitative evaluation of cardiovascular function with several parameters including strain, strain-rate, torsion and mechanical dispersion. This imaging modality allows precise quantification of ventricular and atrial mechanics by directly evaluating myocardial fiber deformation. The purpose of this article is to review the basic principles, current clinical applications and future perspectives of cardiovascular magnetic resonance myocardial feature tracking, highlighting its prognostic implications.

Quantification of biventricular strain and assessment of ventriculo-ventricular interaction in pulmonary arterial hypertension using exercise cardiac magnetic resonance imaging and myocardial feature tracking.

Right ventricular (RV) failure is the main cause of mortality in pulmonary arterial hypertension (PAH). Exercise testing helps identify early RV maladaptation and systolic dysfunction and facilitates therapy. Myocardial strain has been shown to be more sensitive than ejection fraction (EF) in detecting subclinical ventricular contractile dysfunction. Chronic pressure overload in PAH had been associated with changes in left ventricular (LV) filling. To compare biventricular strains and ventriculo-ventricular interaction in PAH and controls using cardiac magnetic resonance feature tracking (cMRI-FT) and to determine the reproducibility of strain analysis. Prospective. Nine PAH and nine control subjects. 1.5T MRI balanced steady state free precession. RV and LV longitudinal strain (EllRV and EllLV ) were derived using the mid-axial images. Radial (ErrLV ) and circumferential strain (EccLV ) were derived using the mid-ventricular short-axis images. Relationships between strain and volumetric parameters were assessed at rest and during submaximal in-magnet exercise. Comparison of rest-to-exercise data between PAH and controls was analyzed using two-way repeated measures analysis of variance. The relationship between volumetric parameters and cMRI-FT were assessed using Pearson's correlation. Reproducibility was assessed by using Bland-Altman plots. PAH had significantly lower EllRV at rest (-16.6 ± 2.7 vs. -20.1 ± 3.6, P = 0.03) despite normal RVEF. During exercise, RV systolic contractile reserve measured by EllRV was significantly reduced in PAH (PInteraction = 0.02). In PAH, indexed RV end-systolic volume (ESVi) significantly correlated with EccLV and ErrLV at rest (r = -0.65 and r = -0.70, P < 0.05) and with ErrLV during exercise (r = -0.43, P < 0.05). High observer agreement was demonstrated. Despite normal resting RVEF, RV systolic function and contractile reserve as measured by EllRV was significantly reduced in PAH. The close relation between RVESVi with EccLV and ErrLV provides evidence of systolic ventriculo-ventricular interaction in PAH. Exercise cMRI-FT may provide a quantitative metric for detection of subclinical RV dysfunction in PAH. 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;49:1427-1436.

Left ventricular myocardial deformation in Takotsubo syndrome: a cardiovascular magnetic resonance myocardial feature tracking study.

This study assessed the applicability and prognostic value of cardiovascular magnetic resonance (CMR) left ventricular deformation analysis in Takotsubo syndrome (TTS). CMR-feature tracking was performed blinded in a core laboratory to determine circumferential (CS), radial (RS) and longitudinal strain (LS) in 141 TTS patients participating in this cohort study. A subgroup of consecutive TTS patients (n = 20) was compared with age- and sex-matched controls with anterior ST-segment elevation myocardial infarction (STEMI) and non-STEMI as well as healthy subjects. Median global CS, RS and LS were -19%, 19% and -12%, respectively. Apical ballooning was associated with significantly lower global CS (p < 0.01) and LS (p < 0.01) compared with midventricular and basal ballooning. Global RS was lowest in patients with basal ballooning (p < 0.01). Segmental analysis resulted in a reliable discrimination of different ballooning patterns using CS and LS. Strain values were significantly lower in TTS compared with non-STEMI patients and healthy subjects, whereas STEMI patients showed similar values. While global CS and RS were not associated with long-term mortality, global LS (cutoff -14.75%) was identified as a potential parameter for long-term risk stratification (mortality rate 17.9% versus 2.5%; p = 0.02). The transient contraction abnormalities in TTS can be quantitatively assessed with CMR-feature tracking. GLS is a potential determinant of outcome in TTS, which, however, requires further validation. • Cardiovascular magnetic resonance myocardial feature tracking enables accurate assessment of regional and global left ventricular dysfunction in Takotsubo syndrome (TTS). • Global strain in TTS is similar to patients with anterior STEMI and lower compared with non-STEMI and healthy subjects. • Global longitudinal strain is a potential tool for risk prediction in TTS patients.

Cardiac Magnetic Resonance Myocardial Feature Tracking for Optimized Prediction of Cardiovascular Events Following Myocardial Infarction

ObjectivesThe aims of the study were to assess the prognostic significance of cardiac magnetic resonance myocardial feature tracking (CMR-FT) in a large multicenter study and to evaluate the most potent CMR-FT predictor of hard clinical events following myocardial infarction (MI). BackgroundCMR-FT is a new method that allows accurate assessment of global and regional circumferential, radial, and longitudinal myocardial strain. The prognostic value of CMR-FT in patients with reperfused MI is unknown. MethodsThe study included 1,235 MI patients (n = 795 with ST-segment elevation MI and 440 with non–ST-elevation MI) at 15 centers. All patients were reperfused by primary percutaneous coronary intervention. Central core laboratory–masked analyses were performed to determine left ventricular (LV) circumferential, radial, and longitudinal strain. The primary clinical endpoint of the study was the occurrence of major adverse cardiac events within 12 months after infarction. ResultsPatients with cardiovascular events had significantly impaired CMR-FT strain values (p < 0.001 for all). Global longitudinal strain was identified as the strongest CMR-FT parameter of future cardiovascular events and emerged as an independent predictor of poor prognosis following MI even after adjustment for established prognostic markers. Global longitudinal strain provided an incremental prognostic value for all-cause mortality above LV ejection fraction (c-index increase from 0.65 to 0.73; p = 0.04) and infarct size (c-index increase from 0.60 to 0.78; p = 0.002). ConclusionsCMR-FT is a superior measure of LV function and performance early after reperfused MI with incremental prognostic value for mortality over and above LV ejection fraction and infarct size. (Abciximab i.v. Versus i.c. in ST-segment elevation Myocardial Infarction [AIDA STEMI]; NCT00712101; Thrombus Aspiration in ThrOmbus Containing culpRIT Lesions in Non-ST-Elevation Myocardial Infarction [TATORT-NSTEMI]; NCT01612312)